121951989 has 24 divisors (see below), whose sum is σ = 184143960. Its totient is φ = 77672448.

The previous prime is 121951987. The next prime is 121952011. The reversal of 121951989 is 989159121.

121951989 is a `hidden beast` number, since 121 + 9 + 519 + 8 + 9 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2377764 + 119574225 = 1542^2 + 10935^2 .

It is not a de Polignac number, because 121951989 - 2¹ = 121951987 is a prime.

It is a super-2 number, since 2×121951989² = 29744575242112242, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121951987) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22909 + ... + 27725.

It is an arithmetic number, because the mean of its divisors is an integer number (7672665).

Almost surely, 2^121951989 is an apocalyptic number.

It is an amenable number.

121951989 is a deficient number, since it is larger than the sum of its proper divisors (62191971).

121951989 is a wasteful number, since it uses less digits than its factorization.

121951989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4949 (or 4946 counting only the distinct ones).

The product of its digits is 58320, while the sum is 45.

The square root of 121951989 is about 11043.1874474719. The cubic root of 121951989 is about 495.9024980151.

The spelling of 121951989 in words is "one hundred twenty-one million, nine hundred fifty-one thousand, nine hundred eighty-nine".